This invention relates to clamping devices for holding a workpiece during assembly or manufacture. More specifically, it relates to an adjustable clamp having a locking clamp spindle that is adjustably positionable in a clamping arm, wherein the spindle can be maintained in a desired position in the arm by means of a permanent magnet fixed to the spindle.
Clamps for holding workpieces typically include a clamping spindle that is installed in a pivotable clamp arm and that is adjustably positionable along the length of the clamp arm. The spindle is held in a desired position by means of spindle locking nuts or similar fasteners. To adjust the position of the spindle on the clamp arm, the nuts or fasteners are loosened, and the spindle is re-positioned. Movement of the clamp arm between its raised and lowered positions while the nuts or fasteners are loose can result in the spindle shifting from its desired position. Thus, adjustment of the spindle position to accommodate workpieces of differing shapes and thicknesses requires constant attention to assure that there is no shifting of the spindle when the clamp arm is moved before the spindle locking nuts are tightened. Even with the exercise of such caution, some inadvertent shifting frequently occurs, with resultant inconsistency of results.
It would therefore be an advantage over the prior art to provide a clamp spindle positioning mechanism that allows the adjustment of the spindle position on the clamp arm, while maintaining a set position as the clamp arm is rotated between its raised and lowered positions.